Origin of modern species of mollusks as inferred from their fossils

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400499
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Kochi University
• Principal Investigator: Kondo Yasuo 高知大学, 自然科学系, 教授 (90192583)
• Co-Investigator(Kenkyū-buntansha): NOBUHARA TAKAMI 静岡大学, 教育学部, 教授 (30262843) ; MATSUBARA TAKASHI 北海道教育大学, 教育学部, 准教授 (30311484) ; SASAKI TAKENORI 東京大学, 総合研究博物館, 准教授 (70313195) ; KURIHARA YUKITO 三重大学, 教育学部, 准教授 (10446578) ; NAKAO KENICHI 徳島県立博物館, 上席学芸員 (40372221) ; KIKUCHI NAOKI 兵庫県立人と自然の博物館, 研究員 (60748101)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 軟体動物 / 進化 / 化石 / 祖先種 / 寒冷化

Outline of Final Research Achievements

Comparative analysis of the four pairs of the modern molluscan species, Fulvia mutica, Glycymeris vestita, Umbonium (Suchium) giganteum, U. (S.) costatum, and their ancestors, indicated that, each modern species appeared from Gelasian to Calabrian stages when climatic cooling occurred, near the northern limit of the distribution. Each descendant modern species is distributed in the temperate zone, while the ancestor species in the subtropical zone, and is larger than its ancestor species. In addition, each descendant species inhabits more sheltered or shallower seas. At least some of these characteristics are common. These suggest that speciation of these mollusks occurred in sheltered seas near the northern limit of distribution from the Gelasian to Calabrian stages when climatic cooling accelerated.

Free Research Field

古生物学